1. Field of the Invention
This invention concerns a device for forming a selvedge or selvedges on cloths, ie. a device for use on weaving machines in order to make at least one selvedge during the weaving process. In particular, this invention concerns a device for forming at least one selvedge using one needle thread and up to two crossing threads per selvedge.
2. Discussion of Related Information
Techniques for forming a selvedge on cloth are common technology, and various selvedge-forming devices are known. German utility model No. 8316232 describes a selvedge-forming device in which the motion of the various parts is controlled by the motion of the lead frames or harnesses. Such devices have the disadvantage that the operating cycle of the selvedge-forming device cannot be set independently, but is determined by the motion of particular harnesses. The vibration of the harnesses has a detrimental effect on the operation of the device, due to the wear and consequent danger of breakage.
Swiss patent No. 564.114 describes a device for forming a selvedge using mechanical pushers to impart the necessary motion. However this type of device has the disadvantage that it is not suitable for high weaving speeds, due to the effects of wear and the danger of breakage.
German utility model No. 8208089 describes a method of controlling the movement of the crossing threads via the motion of a slide block with thread guide openings in the form of slanting slits. However, since there is no positive control of the crossing thread motion there cannot be absolute certainty as to the position of the crossing threads.
Various other selvedge-forming devices are known whose main disadvantage is their complicated mechanical construction. An example of such a device is found in German patent No. 1.816.407.